[PATCH 3.2 07/87] ath9k_htc: check for underflow in ath9k_htc_rx_msg()

[Ben Hutchings]

3.2.77-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit 3a318426e09a9c9266fe6440842e11238f640a20 upstream.

We check for overflow here, but we don't check for underflow so it
causes a static checker warning.

Fixes: fb9987d0f748 ('ath9k_htc: Support for AR9271 chipset.')
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/wireless/ath/ath9k/htc_hst.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/ath/ath9k/htc_hst.c
+++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
@@ -377,7 +377,7 @@ void ath9k_htc_rx_msg(struct htc_target
 	htc_hdr = (struct htc_frame_hdr *) skb->data;
 	epid = htc_hdr->endpoint_id;
 
-	if (epid >= ENDPOINT_MAX) {
+	if (epid < 0 || epid >= ENDPOINT_MAX) {
 		if (pipe_id != USB_REG_IN_PIPE)
 			dev_kfree_skb_any(skb);
 		else